Land Cover and Climate Change May Limit Invasiveness of Rhododendron ponticum in Wales

Abstract

Invasive plant species represent a serious threat to biodiversity precipitating a sustained global effort to eradicate or at least control the spread of this phenomenon. Current distribution ranges of many invasive species are likely to be modified in the future by land cover and climate change. Thus, invasion management can be made more effective by forecasting the potential spread of invasive species. Rhododendron ponticum (L.) is an aggressive invasive species which appears well suited to western areas of the UK. We made use of MAXENT modeling environment to develop a current distribution model and to assess the likely effects of land cover and climatic conditions (LCCs) on the future distribution of this species in the Snowdonia National park in Wales. Six global circulation models (GCMs) and two representative concentration pathways (RCPs), together with a land cover simulation for 2050 were used to investigate species' response to future environmental conditions. Having considered a range of environmental variables as predictors and carried out the AICc-based model selection, we find that under all LCCs considered in this study, the range of R. ponticum in Wales is likely to contract in the future. Land cover and topographic variables were found to be the most important predictors of the distribution of R. ponticum. This information, together with maps indicating future distribution trends will aid the development of mitigation practices to control R. ponticum.

Evidence of ecological niche shift in Rhododendron ponticum (L.) in Britain: Hybridization as a possible cause of rapid niche expansion

“…However, like most invasive species, R. ponticum does not lend itself to the provision of autecological information, which makes it difficult to a priori select a specific set of biologically relevant predictors. Following a detailed literature review, we chose 19 bioclimatic variables to model the distribution of R. ponticum (Manzoor, Griffiths, Iizuka, et al, ). Current (1960–2000) climate data were downloaded from the WorldClim database (Fick & Hijmans, ) at a resolution of 30 arc‐seconds (ca.…”

“…Current (1960–2000) climate data were downloaded from the WorldClim database (Fick & Hijmans, ) at a resolution of 30 arc‐seconds (ca. 1 km 2 ), which was shown to provide optimal prediction of R. ponticum distribution (Manzoor, Griffiths, Iizuka, et al, ). The WorldClim (version 2.0) database consists of 19 derived bioclimatic variables that represent climate average, extremes and variability.…”

“…Invasive species replace native vegetation, which often leads to an alteration of ecosystem structure and function due to the simplification of plant community. Biological invasion may cause a disruption of nutrient cycles, reduction of soil health, and a decrease of net primary productivity (Manzoor, Griffiths, Iizuka, & Lukac, ). Understanding the factors that define the geographic distribution of a species, and prevent it from invading other environments, is one of the fundamental goals in ecology.…”

“…Rhododendron ponticum was introduced to the British Isles as an ornamental plant from mainland Europe in the eighteenth century. It is a perennial, evergreen shrub that generally invades woodlands (Tiedeken & Stout, ), although it is known to colonize other types of habitats too (Manzoor, Griffiths, Iizuka, et al, ). The success of the invasion of R. ponticum in Britain is attributed to its ecological and biological characteristics; it produces copious amounts of seeds and can tolerate shaded and nutrient‐depleted soils (Dehnen‐Schmutz & Williamson, ).…”

“…disruption of nutrient cycles, reduction of soil health, and a decrease of net primary productivity (Manzoor, Griffiths, Iizuka, & Lukac, 2018). Understanding the factors that define the geographic distribution of a species, and prevent it from invading other environments, is one of the fundamental goals in ecology.…”